The Company and its Subsidiaries	9 Months Ended
Sep. 30, 2017
Accounting Policies [Abstract]
The Company and its Subsidiaries	Note 1: The Company and its Subsidiaries WMIH Corp. WMIH Corp. (“WMIH”) is a corporation duly organized and existing under the laws of the State of Delaware. On May 11, 2015, WMIH merged with its parent corporation, WMI Holdings Corp., a Washington corporation (“WMIHC”), with WMIH as the surviving corporation in the merger (the “Merger”). The Merger occurred as part of the reincorporation of WMIHC from the State of Washington to the State of Delaware effective May 11, 2015 (the “Reincorporation Date”). WMIH, formerly known as WMIHC and Washington Mutual, Inc. (“WMI”), is the direct parent of WM Mortgage Reinsurance Company, Inc., a Hawaii corporation (“WMMRC”), and WMI Investment Corp., a Delaware corporation (“WMIIC”). Since the emergence from bankruptcy on March 19, 2012, our business activities consist of operating WMMRC’s legacy reinsurance business in runoff mode. In addition, we are actively seeking acquisition opportunities across a broad array of industries with a specific focus in the financial services industry, including targets with consumer finance, specialty finance, leasing and insurance operations. As of September 30, 2017, WMIH was authorized to issue up to 3,500,000,000 shares of common stock, and up to 10,000,000 shares of preferred stock (in one or more series), in each case with a par value of $0.00001 per share. As of September 30, 2017 and December 31, 2016, 206,714,132 and 206,380,800 shares, respectively, of WMIH’s common stock were issued and outstanding. As of September 30, 2017 and December 31, 2016, 1,000,000 shares of WMIH’s Series A Convertible Preferred Stock (the “Series A Preferred Stock”) were issued and outstanding. As of September 30, 2017 and December 31, 2016, 600,000 shares of WMIH’s 3% Series B Convertible Preferred Stock (the “Series B Preferred Stock”) were issued and outstanding. While we remain committed to consummating an acquisition, we also are mindful that the Company’s Series B Preferred Stock is redeemable on January 5, 2018 if we have not consummated a Qualified Acquisition, as more fully described in Note 6: Service Agreements and Related Party Transactions, or executed a definitive agreement to consummate an Acquisition (as such term is defined in Article VI of WMIH’s Amended and Restated Certificate of Incorporation (the “Certificate of Incorporation”)), prior to that date. Accordingly, as previously disclosed, we formed the Finance Committee of the Company’s Board of Directors (the “Finance Committee”), comprised solely of independent directors, to explore potential financing and refinancing alternatives, including the potential restructuring or refinancing of the Series B Preferred Stock. The Finance Committee has retained financial advisors to provide certain financial advisory services in connection with the Finance Committee’s mandate to review the Company’s capital structure and potential financing alternatives. There can be no assurance that any transaction, including a refinancing of the Series B Preferred Stock, will occur or if so on what terms. WMMRC WMMRC is a wholly-owned subsidiary of WMIH. Prior to August 2008 (at which time WMMRC became a direct subsidiary of WMI), WMMRC was a wholly-owned subsidiary of FA Out-of-State Holdings, Inc., a second-tier subsidiary of Washington Mutual Bank (“WMB”) and third-tier subsidiary of WMI. WMMRC is a pure captive insurance company domiciled in the State of Hawaii. WMMRC was incorporated on February 25, 2000, and received a Certificate of Authority, dated March 2, 2000, from the Insurance Division of the State of Hawaii. WMMRC was originally organized to reinsure private mortgage insurance risk for seven primary mortgage insurers then offering private mortgage insurance on loans originated or purchased by former subsidiaries of WMI. The seven primary mortgage insurers are United Guaranty Residential Insurance Company (“UGRIC”), Genworth Mortgage Insurance Corporation (“GMIC”), Mortgage Guaranty Insurance Corporation (“MGIC”), PMI Mortgage Insurance Company (“PMI”), Radian Guaranty Incorporated (“Radian”), Republic Mortgage Insurance Company (“RMIC”) and Triad Guaranty Insurance Company (“Triad”). Due to the then deteriorating performance in the mortgage guarantee markets and the closure and receivership of WMB, the reinsurance agreements with each of the primary mortgage insurers were terminated or placed into runoff during 2008. The agreements with UGRIC and Triad were placed into runoff effective May 31, 2008. The agreements with all other primary mortgage insurers were placed into runoff effective September 26, 2008. As a result, effective September 26, 2008, WMMRC’s continuing operations consisted solely of the runoff of coverage associated with mortgages placed with the primary mortgage carriers prior to September 26, 2008. In runoff, an insurer generally writes no new business but continues to service its obligations under in force policies and otherwise continues as a licensed insurer. The reinsurance agreements with Triad, PMI and UGRIC were commuted on August 31, 2009, October 2, 2012 and April 3, 2014, respectively, and the related trust assets were distributed in accordance with the commutation agreements. On October 23, 2017, the reinsurance agreement with Radian was commuted and the related trust assets were released to WMMRC. On September 13, 2017, the Insurance Division of the State of Hawaii approved this commutation and a related distribution of up to $10.7 million to WMIH, which distribution has not been completed as of the date of the filing of this Form 10-Q. For more information see Note 14: Subsequent Events. As a result, WMMRC’s current continuing operations, subsequent to the Radian commutation, consist solely of the runoff of coverage associated with mortgages placed with the following three remaining carriers, GMIC, MGIC and RMIC. WMIIC WMIIC does not currently have any operations and is fully eliminated upon consolidation.

Note 1: The Company and its Subsidiaries

WMIH Corp.

WMIH Corp. (“WMIH”) is a corporation duly organized and existing under the laws of the State of Delaware. On May 11, 2015, WMIH merged with its parent corporation, WMI Holdings Corp., a Washington corporation (“WMIHC”), with WMIH as the surviving corporation in the merger (the “Merger”). The Merger occurred as part of the reincorporation of WMIHC from the State of Washington to the State of Delaware effective May 11, 2015 (the “Reincorporation Date”).

WMIH, formerly known as WMIHC and Washington Mutual, Inc. (“WMI”), is the direct parent of WM Mortgage Reinsurance Company, Inc., a Hawaii corporation (“WMMRC”), and WMI Investment Corp., a Delaware corporation (“WMIIC”). Since the emergence from bankruptcy on March 19, 2012, our business activities consist of operating WMMRC’s legacy reinsurance business in runoff mode. In addition, we are actively seeking acquisition opportunities across a broad array of industries with a specific focus in the financial services industry, including targets with consumer finance, specialty finance, leasing and insurance operations.

As of September 30, 2017, WMIH was authorized to issue up to 3,500,000,000 shares of common stock, and up to 10,000,000 shares of preferred stock (in one or more series), in each case with a par value of $0.00001 per share. As of September 30, 2017 and December 31, 2016, 206,714,132 and 206,380,800 shares, respectively, of WMIH’s common stock were issued and outstanding. As of September 30, 2017 and December 31, 2016, 1,000,000 shares of WMIH’s Series A Convertible Preferred Stock (the “Series A Preferred Stock”) were issued and outstanding. As of September 30, 2017 and December 31, 2016, 600,000 shares of WMIH’s 3% Series B Convertible Preferred Stock (the “Series B Preferred Stock”) were issued and outstanding.

While we remain committed to consummating an acquisition, we also are mindful that the Company’s Series B Preferred Stock is redeemable on January 5, 2018 if we have not consummated a Qualified Acquisition, as more fully described in Note 6: Service Agreements and Related Party Transactions, or executed a definitive agreement to consummate an Acquisition (as such term is defined in Article VI of WMIH’s Amended and Restated Certificate of Incorporation (the “Certificate of Incorporation”)), prior to that date. Accordingly, as previously disclosed, we formed the Finance Committee of the Company’s Board of Directors (the “Finance Committee”), comprised solely of independent directors, to explore potential financing and refinancing alternatives, including the potential restructuring or refinancing of the Series B Preferred Stock. The Finance Committee has retained financial advisors to provide certain financial advisory services in connection with the Finance Committee’s mandate to review the Company’s capital structure and potential financing alternatives. There can be no assurance that any transaction, including a refinancing of the Series B Preferred Stock, will occur or if so on what terms.

WMMRC

WMMRC is a wholly-owned subsidiary of WMIH. Prior to August 2008 (at which time WMMRC became a direct subsidiary of WMI), WMMRC was a wholly-owned subsidiary of FA Out-of-State Holdings, Inc., a second-tier subsidiary of Washington Mutual Bank (“WMB”) and third-tier subsidiary of WMI. WMMRC is a pure captive insurance company domiciled in the State of Hawaii. WMMRC was incorporated on February 25, 2000, and received a Certificate of Authority, dated March 2, 2000, from the Insurance Division of the State of Hawaii.

WMMRC was originally organized to reinsure private mortgage insurance risk for seven primary mortgage insurers then offering private mortgage insurance on loans originated or purchased by former subsidiaries of WMI. The seven primary mortgage insurers are United Guaranty Residential Insurance Company (“UGRIC”), Genworth Mortgage Insurance Corporation (“GMIC”), Mortgage Guaranty Insurance Corporation (“MGIC”), PMI Mortgage Insurance Company (“PMI”), Radian Guaranty Incorporated (“Radian”), Republic Mortgage Insurance Company (“RMIC”) and Triad Guaranty Insurance Company (“Triad”).

Due to the then deteriorating performance in the mortgage guarantee markets and the closure and receivership of WMB, the reinsurance agreements with each of the primary mortgage insurers were terminated or placed into runoff during 2008. The agreements with UGRIC and Triad were placed into runoff effective May 31, 2008. The agreements with all other primary mortgage insurers were placed into runoff effective September 26, 2008. As a result, effective September 26, 2008, WMMRC’s continuing operations consisted solely of the runoff of coverage associated with mortgages placed with the primary mortgage carriers prior to September 26, 2008. In runoff, an insurer generally writes no new business but continues to service its obligations under in force policies and otherwise continues as a licensed insurer. The reinsurance agreements with Triad, PMI and UGRIC were commuted on August 31, 2009, October 2, 2012 and April 3, 2014, respectively, and the related trust assets were distributed in accordance with the commutation agreements. On October 23, 2017, the reinsurance agreement with Radian was commuted and the related trust assets were released to WMMRC. On September 13, 2017, the Insurance Division of the State of Hawaii approved this commutation and a related distribution of up to $10.7 million to WMIH, which distribution has not been completed as of the date of the filing of this Form 10-Q. For more information see Note 14: Subsequent Events. As a result, WMMRC’s current continuing operations, subsequent to the Radian commutation, consist solely of the runoff of coverage associated with mortgages placed with the following three remaining carriers, GMIC, MGIC and RMIC.

WMIIC

WMIIC does not currently have any operations and is fully eliminated upon consolidation.